In general, control knobs, for example, a display type control knob, such as a change knob on the transmission gear of a vehicle, a push type control knob, such as the start button of a vehicle, and a rotation type control knob, such as the volume control dial of audio, are applied to vehicles or electronic products in various ways.
In the control knobs, a common control knob simply made of synthetic resins is used a lot, but a light-emitting control knob for emitting light, supplied from underlying light-emitting devices, through light-emitting display windows having a character or sign form externally in order to provide a beautiful and high-class design and also increase visibility has recently been in the spotlight.
A conventional light-emitting control knob has a construction in which a light-blocking layer is stacked and formed in the remaining parts other than light-emitting display windows having a character or sign form by way of painting or depositing so that the light-emitting display windows are formed on a top surface of the knob body made of synthetic resins.
The conventional light-emitting control knob, however, is problematic in that the light-blocking layer is discolored when the control knob is used for a long period or the light-blocking layer is peeled off due to frication with a user's hand because the light-blocking layer is formed and stacked on the top surface of the knob body by way of painting or depositing. The conventional light-emitting control knob is also problematic in that a user is soon tired of the control knob because the light-blocking layer having a single color is stacked and thus the user's preference to a design part is not satisfied.